The present invention relates to a device forming a mouthpiece for a snorkel or diving regulator for underwater communication, adapted to convert mechanical vibrations into electrical signals and vice versa.
A mouthpiece of this kind, as currently known and described, particularly in EP-487,599, comprises a transducer buzzer positioned in a watertight way in said mouthpiece in the proximity of, or at least partially within, a bite tab, in such a way as to provide transmission of electrical signals to the inner ear through the jawbones.
However, the auditory quality of the sound reproduced, both in transmission and reception, by the existing mouthpieces designed according to this technology is considered to be insufficient at the present time.
The present invention is designed to overcome this problem and has the essential object of providing a mouthpiece for a snorkel or diving regulator which can improve the auditory quality of the reproduced sound, both in transmission and in reception.
Another object of the invention is to provide a convenient and reliable mouthpiece which is sufficiently robust to be durable over a period of time in operating conditions.
For this purpose, the invention aims to provide a device forming a mouthpiece for a snorkel or diving regulator, adapted to fit in the mouth of a diver or swimmer, and comprising:
a body provided with an air intake and extended by two lateral branches each provided with a bite tab, and
at least one transducer buzzer positioned in one of the branches and comprising a piezoelectric membrane.
According to the invention, this device is characterized in that each transducer buzzer
comprises a peripheral weight fixed to the periphery of the piezoelectric membrane, and means for transmitting the vibrations of said membrane towards the teeth of the diver or swimmer, and
is positioned in the branch in such a way that the piezoelectric membrane is totally isolated from the external environment, and that the transmission means form a contact interface with the teeth at the bite tab.
In the context of the invention, the terms xe2x80x9clateralxe2x80x9d, xe2x80x9clowerxe2x80x9d and xe2x80x9cupperxe2x80x9d are to be understood as referring to the body when it is fitted in the diver""s mouth. Thus, xe2x80x9clateralxe2x80x9d signifies that the bite tabs face each other at the lateral sides of the mouth.
Accordingly, the invention consists, in the first place, of the provision of a device comprising at least one transducer buzzer adapted to convert mechanical vibrations into electrical signals and vice versa, said transducer buzzer being positioned, on the one hand, in contact with the teeth of the diver or swimmer in order to transmit to the ear via the bones mechanical vibrations conveying the electrical signals received and, on the other hand, to receive the phonemes spoken by the diver.
The transducer buzzer is adapted, in a known way, to be connected to an electronic unit comprising a voltage source, an electrical amplifier, and a sound source or an underwater or wire transmitter and/or receiver, adapted to convert the electrical signals emitted by the transducer buzzer into signals propagated in water or in a wire, and vice versa. This underwater communication device operates as follows:
For reception, the sound source or underwater or wire receiver converts the sounds into electrical signals suitable for being received by the transducer buzzer. This converts the electrical signals received into mechanical vibrations which are transmitted to the inner ear of the diver or swimmer via the teeth and the bones. The diver or swimmer then hears the messages sent by another diver, or the sounds sent by the sound source.
For transmission, the phonemes spoken by the diver or swimmer generate mechanical vibrations of the teeth, which are received by the transducer buzzer which is in contact with the teeth. These mechanical vibrations are converted by the transducer buzzer into electrical signals and transmitted to the electronic unit.
Additionally, essentially, and according to the invention, each piezoelectric membrane is provided with a peripheral weight which helps to increase the inertia of the periphery of said membrane, and which, in practice, enables the intrinsic characteristics of this membrane to be modified in an advantageous way.
This is because, in practice, such a weight makes it possible to obtain a flatter spectrum over the whole audio band, and thus to enhance the quality of the reproduced sounds to a significant degree. Moreover, this weight forms a protective frame for the membrane which additionally helps to increase the rigidity of the membrane.
According to the invention, the term xe2x80x9cweightxe2x80x9d denotes a massive object fixed to the circumference of the piezoelectric membrane and in contact with said circumference only. If the piezoelectric membrane comprises a piezoelectric disk fixed to a flexible support disk, the weight can also consist of an increased thickness of said flexible support disk. It can also consist of an attached piece fixed to the periphery of the piezoelectric membrane.
However, if the piezoelectric membrane comprises a piezoelectric disk fixed to a flexible support disk, the peripheral weight advantageously forms the peripheral edge, fixed to said membrane, of a hollow isolating casing for the piezoelectric disk, which has a shape permitting the vibration of the piezoelectric membrane.
Such a casing allows the piezoelectric disk to be electrically isolated in a differential way by forming a metallic cage which isolates the disk from the external environment. Moreover, it also isolates the piezoelectric disk mechanically from the external environment, and, on the one hand, prevents the ingress of water, and, on the other hand, prevents any migration towards the mouth of the products forming this disk.
Additionally, and advantageously, the volume delimited by the casing and the piezoelectric membrane is filled with an incompressible fluid or gel which permits the vibration of said piezoelectric membrane.
This filling of the casing ensures that the piezoelectric membrane is mechanically protected against variations of pressure in the environment in the following circumstances:
during the molding of the mouthpiece, in the course of which each transducer buzzer is overmolded with a material such as liquid silicone, and
during diving.
Additionally, and advantageously, the volume delimited by the casing and the piezoelectric membrane is filled with gel, such as a silicone dielectric gel, and encloses an air bubble.
Such an air bubble makes it possible to decrease the constraints imposed by the gel on the deformations of the piezoelectric membrane, and thus promotes the vibration of the membrane.
Additionally, in order to produce this air bubble, the wall of the casing is advantageously pierced axially with an orifice blocked with a seal, and has a thickness such that said orifice delimits a volume enclosing said air bubble.
In an advantageous example, the casing delimits, together with the piezoelectric membrane, a volume of the order of 300 to 340 mm3, the volume of the air bubble being approximately in the range from 10 to 30 mm3.
Furthermore, for the sake of convenience, and advantageously, the casing has the general shape of a cap delimiting a chamber of domed shape.
In an advantageous embodiment, the transmission means comprise a stem fixed axially to the piezoelectric membrane and an interface bit mounted on said stem and having a shape adapted to be flush with one of the faces of the bite tab for contact with the teeth.
Additionally, and advantageously, the interface bit has a generally L-shaped face for interface with the teeth which is flush, on the one hand, with the lateral face of the branch, and, on the other hand, with one of the faces of the bite tab for contact with the teeth.
Because of the shape of this lateral bit, the contact between the bit and teeth can be lateral, and the user is therefore not obliged to clench his teeth, so that the risks of marking the bit and causing cramp in the user are diminished. This contact can also be optimal if it is sought by the user in certain situations by biting the bit between the two jawbones.
Additionally, in order to provide in a natural way a better lateral contact with the interface bit, each bite tab is advantageously generally T-shaped, forming, with the lateral face of the present corresponding branch, two areas of contact with the upper and lower teeth, each being generally U-shaped.
According to another advantageous characteristic of the invention, the device comprises two transducer buzzers, each encased in one of the lateral branches of the mouthpiece, said transducer buzzers being linked by a curved bar provided with means of fastening the casings of these transducer buzzers, and having a shape suitable for being encased in the lateral branches and body of said mouthpiece.
In this embodiment, as a result of the presence of the curved bar, it is possible to ensure precise positioning of the complete insert at the time of its overmolding, and consequently to produce a neat mouthpiece in a reproducible way.
Additionally, and advantageously, in order to ensure that the transducer buzzers are held in place, each casing has an intermediate peripheral annular groove formed in the outer face of said casing, the curved bar comprising two end sections in the form of arcs, each adapted to be housed and snap-fitted in the groove of one of the casings.
Additionally, an electrical cable is soldered in a conventional way to the two disks of each transducer buzzer, and, advantageously, each casing is pierced with a hole for the passage of said electrical cable, and the curved bar has a longitudinal guide groove for this electrical cable.
According to another advantageous characteristic, the mouthpiece comprises an electrical connection sleeve within which the electrical cable extends, enabling the mouthpiece to be connected simply and removably to an electronic unit.